These opals have a yellow, orange, red or reddish brown body color, where most opals have a white body color. These opals may have play of color, or may not, but are categorized specifically on their body color. They can be transparent, translucent or opaque. They are found mostly in Mexico and Ethiopia. Opal is made up of Silicon Dioxide, just like quartz crystal. But unlike quartz it contains up to 38% water, but most commonly 3%-16%. Until recently it was believed that all opal was completely amorphous, however now we know that isn’t the case. Some Opal’s contain tightly packed spherical SIO₂ molecules in a hexagonal structure lattice. Not always perfect, but they do have a pattern. There are 2 types of opal; precious and common. Precious Opal displays an optical property that gemologists call, “Play of Color” or Opalescence, and Common Opal does not. Common Opal is usually milky white, grey, yellow/brown or black. Precious Opals display every color that we can see. They do so by diffracting light through their lattice structures. Formed under water by diatom shells that accumulate on sea/river/lake beds. Diatoms are algae that synthesize silicon dioxide in water to use in their cell walls. They produce most of the oxygen on the planet, not trees. Diatoms tend to have massive “blooms” and then die off and sink to the bottom of the water column, where they accumulate in silt. Here is where, over thousands & millions of years, they can fall into seams between rocks, pockets in sediment and slowly take over the skeletal systems of decayed plant matter to form opals. Black Opal is the rarest variety, & white, grey and green are the most common. The biggest Opal producers are Australia, Ethiopia & Nevada. There are very rare opals in Mexico, Oregon, Washington, Idaho & Slovakia. Opal is the birthstone for October.

– Luck, abundance, creativity, and passion.- Enhances intuition & trust in instincts.- Vitality, sexuality, passion.- Comfort in being independent and seeking new directions in life.

Chemical Formula: SiO₂˖nH₂O
Shape: amorphous
Habit: vein fillings and pseudomorphs of organic materials
Color: yellow, orange, red & reddish brown.
Streak: white
Luster: dull, pearly, waxy or vitreous when raw, vitreous when polished
Diaphaneity: translucent, semi-transparent, opaque
Hardness: 5-6 Mohs
Cleavage: none
Fracture: conchoidal
Specific Gravity: 2.09 g/cm³
Refractive Index: 1.34-1.47